Sorry for that. But if I haven't try all known methods, I won't
do this just in order to call the attention of the list master.
To tell the truth, I can't subscribe to any debian mailing lists right
now. I can't quit debian-user, either. Weird.
-Xinjiang

Are you having the e-mail from the list sent to a different address
than the address you are sending your e-mail from?
Hal

I don't think so.
I emailed to Majordomo@lists.debian.org with "which my.email.address" in
the body. I can see my email is subscribing to the debian-user mailing
list.
-Xinjiang

Have you chaecked that the confirmation mails don't get stuck in your
spam filter?

Is it possible?
Then I have to contact the webmaster in my department.
I will look into it.
Thank you so much.
-Xinjiang